Angiogenesis is important for wound healing, tumor growth, and metastasis. The laminin alpha 4 chain, a component of laminin-8 and -9, is expressed in endothelial cell basement membranes. It mediates endothelial cell adhesion by binding with its receptors such as alpha nu beta 3 integrin and participates in new blood vessel formation. In this study, we found the recombinant laminin alpha 4LG modules (rLGI-3, rLG1, and rLG2) mediate HUVECs adhesion. The attachment of HUVECs to the rLG2 was specifically inhibited by a function-blocking monoclonal antibody LM609 specific for alpha nu beta 3 integrin. Using deletion mutants of the alpha 4LG2 revealed the HUVECs-adhesion site is located in amino acids 1121-1139. A synthetic G 1121-1139 peptide could be attached by HUVECs at same efficiency with the rLG2 and promoted angiogenesis in CAM. In conclusion, we have identified a new alpha nu beta 3 integrin-interacting peptide within laminin alpha 4 G domain. This suggests that G(1121-1139) peptide-containing proteins may perform their biological functions by interacting with alpha nu beta 3 integrin. (c) 2006 Elsevier Inc. All rights reserved.